The present invention relates to the management of television facilities, particularly for the purpose of tracking television programs stored, in recorded form, and being transmitted within, the facility, as well as programs being received and transmitted by the facility.
Television programs, prior to broadcast or transmission over a cable system, may be conducted over a wide variety of paths within a facility and between facilities. Up to the present, no system or procedures have been available to reliably monitor the flow of such programs in real time. As a consequence, those managing such facilities generally must rely on the assumption that all operating personnel have taken the necessary steps to route the programs in the desired manner. At present, one of the most feasible procedures for determining what has actually been broadcast or distributed by a cable system is to make an off-air recording of all programs which have been broadcast or distributed to consumers. In other words, this procedure only allows the required determination to be made offline and hence not in real time.
The television industry has implemented several different computer systems and associated software designed to achieve specific objectives, such as the preparation of a log of programs to be broadcast or distributed. Some accounting programs have been developed which make use of manually entered data derived from the log of the programs intended to be broadcast as well as discrepancy reports from operators on duty at the time of broadcast and the viewing of off-air recordings. In addition, some limited automation of on-air programs has been attempted. However, to date, the capability of such systems is limited because, generally, they are not capable of automatically identifying the programs which are being routed through, or are stored in, a facility. Thus, the timely distribution of television programs to consumers, either by broadcasting or by delivery to a cable network, is for the most part, if not entirely, dependent on, and in most instances can only be verified by, the responsible operating personnel.
It is a primary object of the present invention to automatically monitor the routing of television programs, or their elements, within a facility and between facilities in order to permit the automatic generation of a record of the path followed by each television program or element and the time at which each program or element reached each distribution point along its routing path.
A more specific object of the invention is to provide the video signals of each program with information which identifies the program and which can be decoded in a manner to be supplied to a computer system, thereby allowing real time management of a television facility.
Another specific object of the invention is to provide such program identifying information in the region of a video signal which contains picture information, but which does not interfere with viewing of the associated program on a home receiver.
The above and other objects are achieved according to the invention by the provision of apparatus for tracking the flow of television programs within a program distribution system, each program including a video signal which contains information to generate a television picture, the distribution system including a plurality of units through which the television programs flow, the apparatus comprising: first signal processing means connected within the system for adding signal elements to the video signal of a program in order to add patterns of symbols, referred to hereafter as icons, to the television picture such that the symbols are disposed at predetermined locations of the television picture and a plurality of successive patterns constitute a code uniquely identifying the program; and second signal processing means connected within the system for detecting signal elements previously added to a video signal and for producing, in response to such detection, an identification of the program which included the video signal.
Objects according to the invention are further achieved by a method for tracking the flow of television programs within a program distribution system, each program including a video signal which contains information to generate a television picture, the distribution system including a plurality of units through which the television programs flow, the method comprising: adding, in first signal processing means connected within the system, signal elements to the video signal of a program in order to add patterns of symbols, referred to hereafter as icons, to the television picture such that the symbols are disposed at predetermined locations of the television picture and a plurality of successive patterns constitute a code uniquely identifying the program; and detecting, in second signal processing means connected within the system, signal elements previously added to a video signal and producing, in response to such detection, an identification of the program which included the video signal.
Because the elements of a television program are routed through a number of pieces of signal processing equipment before broadcast or delivery to a consumer cable system, these elements are subject to various artifacts and distortions not found in the original program material. Additional artifacts and distortions will, of course, be introduced into television signals during broadcast or distribution over a consumer cable system. All portions of a video signal not contained within the active picture window, also known as the scattered image area, which contains picture information are subject to and indeed are at some point reshaped, retimed, and/or replaced, which can make any information scheme using these areas often unreliable at best. The most reliable place to insert any form of identification scheme is therefore in the active picture area.
One major problem associated with using the active picture area is that the information may be inserted at a location which is objectionable to the viewer.
The present invention obviates, or at least substantially ameliorates, the first of these problems by utilizing icons which are relatively small compared to the picture as a whole, and by inserting these icons into video signals so that, in a picture produced by those signals, these icons will be located in an area of the picture which will no be seen on a properly adjusted home television receiver. This area will be referred to hereafter as the icon area. The outer boundary of the icon area coincides with the boundary of the above-mentioned scattered image area and the inner boundary of the icon area preferably coincides with the boundary of an area known in the art as the safe title area, and more preferably with the boundary of an area known in the art as the safe action area, which is slightly larger than the safe title area. The form and dimensions of these areas will be described below. In a properly adjusted home television receiver, the picture width and height adjustments are set to cause electron beam scanning to correspond to an area slightly larger than the picture tube usable area. Ideally, the adjustments are set so that the safe action area of the picture corresponds to the picture tube usable area.
A second problem is that distortions and artifacts exist when the program is viewed by the consumer. While these distortions may not be objectionable to the consumer, they may still cause unreliability in digital systems.
For example, because of the inherent characteristics of equipment which is currently employed for processing video signals, there are certain obstacles to accurate placement of information at defined locations of a picture area. As regards accurate positioning in the vertical direction, picture line counting is performed using the vertical sync as a reference, and digital video processors and video tape recording time base correctors replace both vertical and horizontal sync pulses. Therefore, the accuracy with which a particular picture line can be determined is a function of each individual piece of equipment employed during the processing. A common problem with some of the more popular video tape recorders is that they can lock to a video signal one line late. The time base corrector will then add sync information so as to shift the picture one line vertically. These shifts go unnoticed by the viewer because the missing line is outside of the picture area normally viewed on a home receiver.
With regard to picture element positions in the horizontal direction, the position of any picture element along a line of actual video is referenced to the leading edge of the horizontal sync pulse for that line. The types of video processing equipment referred to above and even the older analog processing amplifiers have the ability to change this relationship. Again, the viewer is not affected by such changes because they have no reference as to the actual location of the picture edge. In practice, this error is held to approximately one-half cycle of the subcarrier because larger amounts of picture phase error would cause horizontal blanking to expand beyond permissible limits.
Existing equipment also presents problems relating to analog brightness level and linearity of signal amplification. Even distribution amplifiers, which are the simplest element employed in television processing systems, can introduce significant analog errors into signals which they process. These errors include errors relating to differential gain, signal compression, high or low brightness levels, nonlinear transfer functions, etc. More complicated equipment can introduce even higher error levels. Therefore, when digitizing a signal which has passed through any of these devices, quantizing errors are likely to occur.
The elements, or icons, employed to provide information in accordance with the present invention have the capability of retaining their information content even when the video signals in which they are contained are subjected to the various shifts and distortions mentioned above. The icons are constituted by simple patterns which have sufficient redundancy to assure reliable detection even after having been subjected to vertical and horizontal displacements of the type described above. In order to assure reliable decoding even if the icons have been subjected to analog level quantizing errors, each picture frame includes, in a defined area, a specific reference icon having regions which represent picture black, white and gray levels. The difference between the known values of these levels and the pixel values encountered when reading the reference icon gives an indication of the magnitude of gain and linearity errors which occurred subsequent to encoding. This information can be used as offsets in reading the icons recovered from the other three icon areas of a picture frame.
More specifically, the invention enables the problems relating to picture element position shifts and analog signal distortion to be overcome by using icon patterns which can be reliably detected and identified with the aid of currently available technology, employing fuzzy logic, even in the presence of high levels of noise or distortion. As opposed to detection techniques employing the classic Boolean logic, where each signal element can have only one of two values, 0 or 1, fuzzy logic can associate each signal element with a value in a substantially continuous range between 0 and 1. Therefore, fuzzy logic pattern recovery does not rely on a perfect match. It returns a value as to the closeness of a match. Reasonable amounts of noise or distortion do not hamper symbol recovery when the icons are constituted by patterns within parameters contemplated by the present invention, giving the system a robustness not found in Boolean based information systems.